10 BULLETIN 102, UNITED STATES NATIONAL MUSEUM. 
This unprecedented consumption of power, of course, places a heavy 
strain upon transportation, both directly by virtue of the bulk of the 
power materials to be moved — coal alone represents over a third 
of the country’s freight — and indirectly in respect to the haulage of 
materials and products involved in the industrial processes. The re- 
sponsibility thus falling upon transportation is added to in further 
degree by the size of the country. The presence of a population 
scattered over a vast area, wfith a standard of consumption cut to the 
measure of a concentrated industrialism, attaches the element of dis- 
tance to the factor of bulk and imposes an accentuated dependence 
upon adequate carriage. 1 Thus in two respects the transportation 
problem in the United States is unique. 
But national dependence upon transportation, so highly developed 
by virtue of the advanced state of industrialism and the areal extent 
of consumptive demand, is increasing. The rapidly enlarging use 
of power and the growing burden of commodity haulage arising in 
consequence, to say nothing of the claims of foreign trade, give no 
prospect of letting up. Every time an individual adopts a mechani- 
cal appliance or purchases an article hitherto made at home or gone 
without, thousands of others are doing the same thing. Society will 
not turn back now ; presently it can not turn back any more than it 
can to-day weave its own garments by hand. The convenience of 
to-day is the necessity of to-morrow. If we project the present trend 
of requirements even 10 or 15 years into the future, we begin to gain 
a true perspective of the imposing weight of the transportation prob- 
lem that industrialism faces. 
Since transportation is called upon to bear a heavier responsibility 
in the United States than is the case elsewhere in the world, it should 
be observed that there is an element of weakness in the functioning 
of transportation which becomes the point of break under strain 
and therefore merits particular attention in this country. This is 
the matter of differential elasticity as between the operations of in- 
dustry and transportation, which prevents an equalized stretching of 
the two. For example, when a ton of material passes through a 
manufacturing plant it means, with due qualifications, that the rail- 
roads have hauled a ton of raw material from far and wide and will 
move a similar weight of products away for distribution. Thus 
each increment to the volume of manufacture creates a twofold 
addition to the volume of transportation. Induce a stress of indus- 
trial expansion and the stress communicated to transportation is 
correspondingly magnified. The fabric is mechanical in each case; 
but the fabric of industry is woven with the maximum of elasticity, 
while the fabric of transportation is inherently more rigid. Thus 
1 This has nothing to say of further complications in the way of conflicting currents of 
haulage arising from topographical conditions, etc. 
